Methods for dual completion of oil and gas wells



METHODS FOR DUAL COMPLETION OF OIL AND GAS WELLS I Filed June 15, 1953Aug. 12, 1958 M. P LEBOURG I 2 Sheets-Sheet. 1

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' MAURICE P. LEBOURG H IS ATTORNEYS.

P. LEBOURG 2,847,072

I METHODS FOR DUAL COMPLETION OF on. AND GAS WELLS Fild June 15,1953

Aug. 12, 1958 2 Sheets-Sheet 2 '-FIG.4.

INVENTOR. MAURICE RLEBOURG WEWM 54 n. n. 22D U n FIG.3.

HIS ATTORNEYS.

United States Patent '0 METHODS FOR :DUAL COMPLETION OF: OIL AND GASWELLS Maurice P. Lebourg, Houston,Tex,, assignor, by mesne assignments,to Borg-WarnerCoi-poration, Chicago, 11]., a corporation of IllinoisApplication June 15, .1953, .SeriaLNo. 361,583

2 Claims. Cl.j 1 66-46) The present invention'rela'tes -to-rnethods-andmeans enabling fluids such-as oil and gas-to be*produced-simultaneously'and separately from-two vertically-spaced productive formationstraversed'by a borehole, atechnique that will be referred to herein as"-dual well completion.

It has become common field practiceto employ the novel well completionmethods and --apparatus 1 disclosed in copending application- Serial No.209;*598,* filed February 6, 1951, by H. S. Robertson for Methodand*Apparatus forPerforating Well Casing-and theLikef'arid described in anarticle 'entitled A Method QfPerfQra-ting Casing Below Tubing," by M.P.'Lebourg'=and"G.

"Hodgson, at page 303,-vol. 195 (1-952),*'Petroleum"lransactions, AIME.-In accordance with -the principles :set forth therein, a'well iscompleted bysplacing'production equipment at the surface and settingtubing in the 'well prior to perforating. 'However, inmanyoil fields,=itis desirable to produce twodifferent-formations; simultaneously toprovide savings in pipe and-drilling costs. :The producing formationsare often at-difierentpressures and one may produce gas, the other oil.'Ihe two form'ations, under'these conditions, must" of :necessity beproduced separately. It is also desirable to obtain such: productionsimultaneously through the tubing and through the space between thecasing andthe' tubing.

'Accordingly, it is anobject of the present .invention IOLPIDVldB novelmethods: and apparatus forrdual well "completion.

Another object of the invention is .to :providefor: separate andsimultaneous 1' production afrom two-vertically spaced'formationstraversed by a bore hole.

separate and simultaneous production-from two zvertically spacedformations traversed by. azrcasedrbore ,1 hole,=rsuch production being.through tubing and::throughxltherspace between the tubing and easing.

These and other objects ofathe invention. aretaccomuplished by :setting'a production wpackensin the well; :casing lbetween the two formations tehe -produced. nTheproduc- :stion equipment is placed atzthensnrfaceandwtubingtset in" the well": with the lower 1 end: thereof-at-;ai;tposition above the upper productive formation. ZThe. npper andlower formations are then respectively perforated, ,-as,;for example, byperforating apparatus of the type describedin my copending applicationSerial No. 362,214, filed June 17, 1953, for Method and Apparatus forDetonating Explosive Devices in Bore Holes, and/ or by apparatusdescribed in the aforementioned "Robertsontapplication, leaving thetubing end" open. A tubing extension" that passes through the productionpacker is connected to .thetubing, thereby establishingfluid1commu'nication be-- tween the lower formation and-the tubing. Thetwo formations are" effectively separated by the-production 2,847,072Patented Aug, 12, 1958 These and further objects and advantages of theinvention will 'be more fully understood when the following descriptionis read in conjunction with the accompanying drawings, in which:

Fig. 1 is a view in partial cross-section of a typical oil or gas wellin which the first stages of operations in accordance with the inventionare under way;

Fig. 2 is a cross-section view of the well shown in Fig. l, in which thelower producing zone is about to be perforated;

Fig. 3 is a cross-sectional view of thewell, after the tubing extensionis in place; and

Fig. 4 is a detailed view in cross-section of a portion of the tubingextension.

Describing the invention in detail, in Fig. '1, a bore hole 10 linedwith a casing 11 traverses earth formations 12-15, inclusive, theformations 13 and 14 being shown as potentially productive and separatedby the formation '15. The upper end of the bore hole 10 is fitted with awell completion assembly 16, a conventional Christmas tree 17 and alubricator 18.

"Set in the casing 11 opposite the formation 15 is a production packer20 which separates the formations 13 and 14. Formed in the packer 20 isan opening 22 passing vertically therethrough and provided withconventional sealing means 23 therein. The packer 20 is also 1 providedwith conventional outer sealing means 21.

Suspended from the well completion assembly 16 is ;a string of tubing 19with an open lower end 47 (Big. ,2). A'well casing perforating apparatus24 is connected by a head member 25 and a perforated seating-nipple26 tothe tube end 47, a collar '27 securing the nipple 26 :t o the; tubing19. Perforations 49areformed-initlie nipple '26 which are useful forreplacing drilling mud with alighter fluid in the well prior toperforation casing 11, as is more fully described in my aforementionedcopending application Serial No. 362,214. As illustrated in detail inFig. 4, the nipple 26 is provided with sealing inserts 44 and a seatingshoulder 39 for cooperating with -a tubing extension 36, to be morefully described hereinafter.

The perforating apparatus 24 is preferably a shapecl explosive chargeperforating device constructedinaccordance-withthe disclosure'in myabove-mentionedcopendthrough the tubing 19 by a cable 28 carrying aninsulated conductor 29. For simplicity, the detonating device has notbeen shown. A switch 50 is provided to connect the conductor 29selectively to an indicator :51which may be a sensitive galvanometer andto a source of electrical energy 30 for detonating the perforatingapparatus As'shown in detail in Figs. 3 and 4, thetubingem tension 36preferably has perforations -48 -formed in thelower end 43 thereof,although the lower end 43 could Qalso-be formed of screening or be.open. ended. The

-extension 36 is adapted to be lowered into position through the tubing19, as described-ingreater-detail.hereinafter and it has a flangededge38..which is. adapted to seat on a shoulder 39 formed in the .nipple 26.Above the flange 38 is formed a fishing head 40, by.means of which: thetubing extension, 36 may. be .readily,.removed from the well. Suitablemeans, such as a plurality of latches 41, are provided to prevent thetubing extension 36 from being forced upwardly in the tubing 19 underthe pressure of the fluid in casing 11, in normal operation.

In a typical operation, it will be assumed that the well casing 11 hasbeen set, and that the production packer 20, the perforating apparatus24 and the nipple 26 are in position, as shown in Fig. 1. Further, thecable conductor 29 is connected to suitable means suspended on the cable28 for detonating the charges in the perforating apparatus 24. Also, theheavy drilling mud formerly in the well has been depleted and replaced,if at all,

by lighter liquid. 1

With the perforating apparatus 24 positioned adjacent productiveformation 13, as shown, the switch 50 is operated to connect theconductor 29 to the battery 30 resulting in the detonation of thecharges in the perforating apparatus 24 and in the formation in thelower end of the latter of an opening 32, as described in myaforementioned copending application Serial No. 362,214. The explosivejets generated by the charges in the perforating apparatus 24 penetratethe casing 11 forming perforations 31 therein communicating withformation 13 (Fig. 2). If the formation 13 contains oil or gas under ahigh pressure, care must now be observed in manipulating the surfacecontrols on the Christmas tree 17 to prevent the well from blowing outsince the heavy drilling mud has been removed.

The cable 28 is then brought out of the well and the head member 35thereon is secured to well casing perforating apparatus 34 (Fig. 2)which is preferably of the expendable, shaped charge type disclosed inthe aforementioned Robertson application and may include themodifications described in copending application Serial No. 322,017,filed November 22, 1952, by G. R. Hodgson, for Expendable ShapedExplosive Charge Well Casing Perforating Apparatus, and in applicationSerial No. 322,070, filed November 22, 1952, by J. M. Bricaud for BoreHole Detecting Circuit and Bore Hole Firing Circuit Utilizing a CommonTransmission Channel, now U. S. Patent 2,732,518 issued January 24,1956. The circuit disclosed in the latter application includes a casingcollar locator which may be of the type shown in Pagan Patent No.2,558,427. This apparatus is inserted into the lubricator 18 and loweredinto the well by the cable 28 through the tubing 19, the hole 32 in thebottom of the housing for the perforating apparatus 24 and the packer 20to a position adjacent the formation 14.

During the lowering of the perforating apparatus in the well, the switch50 is in the position to connect the conductor 29 to the indicator 51which then receives signals from a casing collar locator in the head 35,enabling the perforating apparatus 34 to be positionedaccuratelyadjacent the formation 14 (Fig. 2). The perforating apparatus34 is then brought to rest and the switch 50 is moved to the position inwhich the source 30 is connected to the conductor 29. This detonates thecharges in the perforating apparatus 34 producing perforations 34a (Fig.3) in the casing'adjacent the formation 14. The nonexpended head member35 may next be raised through the packer 20, the opening 32 in theperforating apparatus 34 and the tubing 19 and removed from thelubricator 18 (Fig. l).

The foregoing operations being completed, the tubing extension 36 ispassed through the tubing 19 until the flanged edge 38 thereof is seatedon the shoulder 39 (Fig. 4) within the nipple 26 and the lowerperforated end is adjacent the formation 14. As shown in Fig. 3, thisprovides a fluid path from the formation 14 through the tubing extension36 and the tubing 19 to the surface of the well. Meanwhile, anotherfluid path is provided from the formation 13 through the space betweenthe casing 11 and the tubing extension 36 and tubing 19 to the surfaceof the earth. The sealing means 23 prevent the passage of fluid from theformation 14 to the interior of the casing 11 above the packer 20 andthe sealing means 44 prevent fluid from the formation 13 from enteringthe tubing 19. Therefore, separate and simultaneous production from bothof the formations 13 and 14 is possible without regard to pressuredifferentials between the formations or the character of the formations,since one may produce oil and the other gas.

Accordingly, the invention provides for obtaining oil and/or gasproduction separately and simultaneously from two vertically spacedproductive formations traversed by a well. Other advantages gained byuse of the invention include the prevention of plugging of theperforations with mud and the reduction of blowout possibilities sincethe casing is perforated after removal of all mud and setting ofproduction tubing.

It should be understood that the embodiments described and illustratedherein are illustrative only. For example, various other casing collarlocators equivalent to that disclosed in the aforementioned Fagan patentmay be incorporated in the system within the scope of the invention.Numerous other modifications of the invention will suggest themselves sothat the specific embodiments described and shown herein are not to beconstrued as limiting the scope of the appended claims.

I claim:

1. A method for completing a well having a casing set therein traversinga plurality of vertically spaced formations of interest and containing acolumn of drilling fluid, comprising the initial steps of settingapertured packer means in said casing between two of said formations,installing production control equipment at the well head, permanentlysetting tubing in said casing to a position adjacent the upper of saidtwo formations, and replacing the drilling fluid with a lighter fluid,and thereafter the subsequent steps of perforating said casing and saidupper and lower formations above and below said packer means, thenlowering tubing extension means within said tubing to extend from thelower end of the tubing and through the aperture in said packer means insealing engagement therewith to said lower formation, and thereafterseparately producing said formations.

2. A method for completing a well having a casing set therein traversinga plurality of vertically spaced formations of interest and containing acolumn of drilling fluid, comprising the initial steps of settingapertured packer means in said casing between two of said formations,installing production control equipment at the well head, permanentlysetting tubing in said casing to a position adjacent the upper of saidtwo formations, and replacing the drilling fluid with a lighter fluid,and thereafter the subsequent steps of perforating said casing and saidupper formation above said packer means, perforating said casing and thelower of said two formations below said packer means, then loweringtubing extension means within said tubing to extend from the lower endof the tubing and through the aperture in said packer means in sealingengagement therewith to said lower formation, and thereafter separatelyproducing said formations.

References Cited in the file of this patent UNITED STATES PATENTS2,033,562 Wells Mar. 10, 1936 2,189,701 Burt et al. Feb. 6, 19402,189,703 Burt et al. Feb. 6, 1940 2,368,428 Saurenman Jan. 30, 19452,543,814 Thompson et al. Mar. 6, 1951 2,689,008 Allen et a1. Sept. 14,1954

